Originally posted by Raybo It's called "Solarography", a piece of film is placed in a "soda can" with a small pin hole directed at the film.
Photo paper is often preferred to film because it is so much slower and thus can be used for much longer exposures. Also, photo paper (B&W anyway) can usually be developed under a safelight, so it's easy to judge when the development is sufficient. I used to play the old trick of putting an 8x10 or 11x14 inch sheet of thin fast photo paper into a round oatmeal carton (Yay, Quaker Oats!) or coffee can with a tinfoil pinhole, for infinite-DOF ultra-wide panos.
(I used thin photo paper as a negative, contact-printed into a thicker sheet for a positive image. Or nowadays, just scan the negative and shoop it as desired.)
Freestyle sells Pinhole-in-a-Paint-Can kits but cheap bastards like me prefer the DIY method. I mean, cartons and cans and tinfoil are cheap; photo paper and chemicals are cheap; many of us have scanners; etc. (Another scanner+printer trick: Print an enlarged digital image onto clear mylar film, then use that as a negative to contact-print onto photo paper.)
For larger-scale pinhole Solargraphs, think of boxes of photo paper, or liquid photo emulsions and fabric. One project: Dig a flat-bottomed hole in the ground. Make a cover with a pinhole. On a dark night, line the bottom of the hole with sheets of photo paper, or with a cloth sheet coated with emulsion. Cover the hole; return in six or eight months. For details, see the book I cited above.
Larger-scale pinhead, er I mean pinhole photography: Instead of a hole in the ground, use a sealed cargo container or boxcar or airplane hangar or the Vehicle Assembly Building at Cape Canaveral as the 'camera'. Larger yet: Put a cover on the Meteor Crater near Flagstaff AZ. Mega-scale: One proposed method to build a starship is to pop a nuke inside a nickel-iron asteroid; a properly shaped charge will produce a BIG cylinder, like an oversized oatmeal carton. Take it from there!